Retractable landing gear for aircraft include a main landing gear and a nose landing gear. The main landing gear may include a side brace for locking the locking gear. The nose landing gear may include a truss brace and a drag brace. Each of these structural braces may employ a lockable hydraulic actuator.
In some landing gears, the hydraulic actuator that acts as the brace may be locked and unlocked by sending an electrical signal to a switch that in turn actuates a key to lock and unlock the actuator. Such a mechanism has been deployed on the Gulfstream G-450 main landing gear. Other lockable actuator designs are disclosed in U.S. Pat. No. 6,832,540, U.S. Pat. No. 6,059,228, U.S. Pat. No. 5,063,828, U.S. Patent Application 2014/0374538 and U.S. Patent Application 2009/0091476.
An improved lockable actuator that is capable of locking in both extended and retracted positions while also providing a lightweight, simple and reliable design would be desirable for a structural brace in a landing gear.